This invention relates to an outdoor unit for a heat pump and more particularly relates to an improved outdoor unit that has sufficient heating capacity under very cold weather conditions.
A heat pump is capable of heating more efficiently than other heating systems. However the heating capacity of a heat pump depends on the temperature surrounding the outdoor unit because the heat pump uses heat that is pumped from the atmosphere surrounding the outdoor unit. Therefore, in a heat pump, the heating capacity and heating efficiency deteriorates according to the decrease in atmospheric temperature. To compensate for this deterioration, Japanese Utility Model Laid Open Print 116161/1985 has suggested the utilization of waste heat from an internal combustion engine by leading the coolant of the engine to the heat exchanger of the outdoor unit.
However the deterioration of the heating capacity and heating efficiency can not be compensated sufficiently under very cold weather conditions because the heat exchanger of the outdoor unit performs as a heat radiator and radiates the waste heat from the heat exchanger to the atmosphere surrounding the outdoor unit.